Recently, various wireless communication technologies have been developed along with the development of information communication technology. Thereamong, wireless local area network (WLAN) is a technology for wirelessly accessing the Internet in the home, companies, or areas for providing a specific service, using a portable terminal such as a personal digital assistant (PDA), a laptop computer, and a portable multimedia player (PMP) based on a wireless frequency technology.
In order to overcome a limit of communication speed pointed out as vulnerability in WLAN, the recent technological standard has introduced a system for increasing speed and reliability of a network and extending a management distance of a wireless network. For example, IEEE 802.11n has introduced a technology of multiple inputs and multiple outputs (MIMO) using multiple antennas in both a transmitter and a receiver in order to support high throughput (HT) with maximum data processing speed of 540 Mbps or more, maximum a transmission error, and optimize a data rate.
A machine-to-machine (M2M) communication technology has been discussed as a next-generation communication technology. The technological standard for supporting M2M communication in an IEEE 802.11 WLAN system has been developed as IEEE 802.11ah. With regard to M2M communication, a scenario of occasionally communicating a small amount of data at low speed in an environment in which numerous devices are present is considered.
Communication in a WLAN system is performed in a medium shared by all devices. When the number of devices is increased like M2M communication, there is a need to more effectively enhance a channel access mechanism in order to reduce unnecessary power consumption and interference.